Relational Model Concepts

The main contents of the chapter consist of the following: Function M-files, syntax of function M-Files, comments, multiple input and output functions, relational model concepts, relational model constraints and relational database schemas, update operations and dealing with constraint violations.

34p nanhankhuoctai10 23-07-2020 21 1   Download

This study makes an original contribution to both of theory and practice through forming and validating the ERP success model for accounting professionals only. In a little more detail, it provides empirical evidence regarding Hunton’s accounting value chain (2002). In addition, it discovers and proves effective use as the most appropriate system-use concept so far. Moreover, it makes an effort to investigate outcomes of accounting benefits perceived from ERP system, which related-studies are much further underresearched.

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The literature offers many definitions of the Lean but it lacks a standard definition that would facilitate its implementation. These definitions are closely related to the specificities of the domain, sector or problem studied. The purpose of this paper is to capture the concepts of the Lean to propose a generic definition independent of the application domain.

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The report proposes the concept of positive boolean dependency in the database model of block form, proving equivalent theorem of three derived types, necessary and sufficient criteria of the derived type, the member problem... In addition, some properties related to this concept in the case of block r degenerated into relation are also expressed and demonstrated here.

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Chapter 2 - The relational model. In this chapter students will be able to: Learn the conceptual foundation of the relational model, understand how relations differ from nonrelational tables, learn basic relational terminology, learn the meaning and importance of keys, foreign keys, and related terminology, understand how foreign keys represent relationships.

41p tangtuy17 11-07-2016 42 2   Download

Learning objectives of this chapter include: Learn how to transform E-R data models into relational designs; practice the normalization process from chapter 2; understand the need for denormalization, learn how to represent weak entities with the relational model; know how to represent 1:1, 1:N, and N:M binary relationships.

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In this chapter, The contents concentrate on describing the basic principles of the relational model of data, begin by defining the modeling concepts and notation of the relational model, discussion of relational constraints that are considered an important part of the relational model and are automatically enforced in most relational DBMSs, defines the update operations of the relational model,...

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Finding groups of objects such that the objects in a group will be similar (or related) to one another and different from (or unrelated to) the objects in other groups. Understanding Group related documents for browsing, group genes and proteins that have similar functionality, or group stocks with similar price fluctuations Summarization Reduce the size of large data sets

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The relational Model of Data is based on the concept of a Relation. A Relation is a mathematical concept based on the ideas of sets. The strength of the relational approach to data management comes from the formal foundation provided by the theory of relations. We review the essentials of the relational approach in this chapter.

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Data Model: A set of concepts to describe the structure of a database, and certain constraints that the database should obey. Data Model Operations: Operations for specifying database retrievals and updates by referring to the concepts of the data model. Operations on the data model may include basic operations and user-defined operations.

34p thienthanoze 12-11-2012 102 10   Download

Real world concepts can be modeled in a computer program The program is made of objects with certain properties and operations that the objects can perform It is not important how an object is implemented, but what it does Every object is responsible for carrying out a set of related tasks. A class can contain data declarations and method declarations

50p nguyenvanhabk1 04-09-2012 69 4   Download